PIX GE and FE hardware have separate structures called queues, for keeping track of the packet buffers. Our FE devices support 128 element queues and our GE devices support 256 element queues. These queues are actually consulted by the hardware, and so the term "hardware" is used when are under consideration.
With regard to the software side, there may exist software queues used by the device driver for tracking packets that are either coming from the hardware input queue or destined for the hardware output queue. For the input side, these are packets that have been taken off the input queue but are still awaiting dispatch to the upper processing layers. For the output side, these are packets that cannot be registered with the driver because the hardware queue is full.
Without seeing the output from the 'sh int' on this PIX, it sounds like your e0 interface is probably sending a lot of packets. The software queue will probably show something like 0/X where X is the max number of software blocks that have been allocated at some time in the past to handle the overflow on the output queue.
Does this make sense?
Scott
